Communication receivers typically include an antenna receiving radio frequency (RF) signals, a cascade of low noise amplifiers amplifying low level RF signals, filters tuning the RF signals at a required frequency, and mixers converting the RF signal to intermediate frequency (IF) signals. In addition, communication receivers include digital circuitry to reproduce a transmitted signal at the receiver end.
In mobile and wireless communications, power is a major criterion in receiver design considerations, followed by device size. Designers attempt to reduce power consumption and device sizes to provide superior battery life and smaller handsets. The devices from the antenna to the mixer are collectively termed as receiver front-end. The receiver front-end provides most of the amplification to the RF signals, reduces signal noise, removes unwanted signals, and converts the RF signals into IF signals for further processing. This stage includes a number of active devices that increase the power consumption considerably.
A typical receiver front-end employs differential signaling. This arrangement requires two pairs of transconductance amplifiers, which together increase the receiver's power consumption and introduce noise. Further, the second pair of transconductance amplifiers degrades overall linearity of the receiver front-end. Existing techniques attempt to reduce the power consumption in the receiver front-end stage. One such technique avoids the use of the second pair of transconductance amplifiers, but the resulting reduction in power consumption comes at the price of degrading the receiver front-end's quality factor and reducing its signal-to-noise ratio (SNR).